A carbon material etc. that stores and releases lithium is currently used as the electrode for lithium batteries, but there is a risk of decomposition of the electrolytic solution since the negative electrode potential is lower than the reductive decomposition potential of the electrolytic solution. Accordingly, as described in Patent Documents 1 or 2, the use of lithium titanate having lower negative electrode potential than the reductive decomposition potential of the electrolytic solution is being investigated, but lithium titanate has a problem of low output property. Accordingly, attempts are being made to improve output property by an electrode in which lithium titanate is made into nanoparticles and supported on carbon.
Patent Document 1: Japanese Patent Application Laid-open No. 2007-160151
Patent Document 2: Japanese Patent Application Laid-open No. 2008-270795
The inventions described in these Patent Documents are methods for applying sheer stress and centrifugal force to a reactant in a rotating reactor to allow promotion of chemical reaction (generally referred to as mechanochemical reaction), thereby yielding dispersed lithium titanate supported on carbon. In this case, for example, titanium alkoxide and lithium acetate which are the starting materials of lithium titanate, a carbon such as carbon nanotube or carbon black, and acetic acid etc. are used as reactants.
Although the electrodes that use carbon supporting lithium titanate crystal structures described in these Patent Documents exert superior output property, there are recent demands to further improve the output property and to improve the electric conductivity in this type of electrode.